Epithelial cells are an important and protective part of nearly all inner and outer barriers of our body. Just focus on the biggest barrier system, the skin, you can imagine the importance of epithelial cells as they are the barrier-forming cells. Further outer barriers are the colon and lung and epithelial cells also are the outer layers of blood vessels and organs.
Besides healthy cells, epithelial tissue accounts for up to 90 % of all cancer cases with epithelial origin.
Epithelial cells are widely used for in vitro barrier systems (skin, colon and lung) as a safety tool and in cancer research.